1. Field of the Invention
The invention relates to a needle bar, suitable for use in needle fields of textile machines, in particular drawing or gill fields of needle bar drawers, also termed gill boxes and, in particular, concerns needle bars with at least one needle rod secured to a carrier bar of the needle bar, this needle bar including a profile-like angled carrier rod and at least one row of needles, the shafts of which are bonded to at least one limb of the angled profile of the carrier rod by soldering, welding, or sticking.
2. Description of Prior Art
Such needle bars have long been successful in operation since excellent drawing results are attainable with their help. The known constructions have, however, disadvantages which render the use of differently constructed needle bars desirable. These disadvantages reside in particular in that their repair is very complicated when needles break out and necessitates special devices of the user so that commonly the whole needle bar must be exchanged and the faulty one repaired at the supplier's. Means have therefore been sought to be able to exchange or replace individual needles or groups of needles and to make this feasible on the spot. The route to this end entailed the use of needle strips which are generally manufactured by the connection together of the shafts of the individual needles preferably by welding or by means of steel wires or bands, and which for their part are connected to the carrier bar by means of sticking, soldering, welding, rivetting or screwing.
From CH-PS No. 497562 further needle rods are known which comprise profile-like bent carrier plates which have a U shaped pocket for the reception of the needles. The spacing of the needle tips corresponds to the shaft thickness of the needles so that the needle shafts lie in close contact adjacent to one another. In the region of their shafts the needles are connected by means of a bonding agent, e.g. a solder mass, to each other and to the carrier rod. The latter is provided with a portion extending above the shaft ends which is constructed as a securing flap serving to secure the needle rod to the needle carrier, e.g. a needle bar.
With needle rods of this construction it is possible to produce a needle field with a very close bar spacing in which the exchange of individual needle rods is facilitated. There are, however, some disadvantages which impair their use in the drawing field resp. gill area of needle bar drawers resp. gill boxes. Thus the U shaped enclosure of the needle shafts results in the individual needles not coming free from their mounting when unavoidably over-stressed, as is desired, since otherwise there is the danger of the bending or the twisting of the carrier bar with the consequence of the destruction of whole needle field regions on the appearance of locally occuring load peaks. Furthermore, the necessity of accommodating the entire length of the needles above the securing flap brings about a moment acting as a torsional stress on the carrier bar and the needle plate which leads to a lasting increased loading of the needle bar. Additionally the suggested needle plate has a very low reactive moment in the direction of stressing of the needles so that these must be connected to the carrier bar either absolutely flat or by means of closely spaced connecting elements, which in the latter case again leads to the weakening of the carrier bar.
3. Object of the Invention
The main objects of the invention are therefore to be found in providing for a needle rod which uses, in a simple manner, wholly or partially exchangeable needle carrying elements of high stress bearing ability to which the needles are so anchored that they reliably come free from the needle assembly at a defined loading lying in the region of their breaking strength extending transverse to the needle rod.